Heat-resistant steels are a family of steels that can specially resist high-temperature oxidation and thermal stress. In order to improve its oxidation resistance, creep resistance and comprehensive performance, alloying elements are usually added to the heat-resistant steel. Here we will discuss four important alloy elements in heat-resistant steel, namely niobium, niobium, niobium, niobium and rare earth elements.
Niobium is a kind of low-activity metal element, which has high melting point, strong reducing and carbide forming ability, and good physical and chemical properties. It is usually added to heat-resistant steel, which can improve its oxidation resistance, especially at high temperature and atmospheric corrosion resistance. In addition, niobium can also reduce the harmful effect of carbide on the toughness of steel, and increase the wear resistance and fatigue strength of steel.
Tantalum is an active rare metal element. After being added to heat-resistant steel, it can not only improve the oxidation resistance of steel, but also form a protective layer on the surface of steel, thus delaying the oxidation of steel in high temperature atmosphere and improving the service life of steel. In addition, tantalum can also improve the cutting performance of steel and reduce the cost of cutting.
Boron is another active element often included in heat-resistant steels. It can not only increase the solid dissolution rate of alloying elements in heat-resistant steel, but also improve the stability of austenite, thus improving the strength and creep resistance of steel. In addition, boron can also improve the machinability of steel and reduce the wear of tool during cutting.
Rare earth elements include a variety of elements such as yttrium, cerium and lanthanum, which are widely used in many fields. In heat-resistant steel, the addition of rare earth elements can reduce the secondary segregation of precipitates and improve the corrosion resistance, mechanical properties and welding performance of steel.
In summary, niobium, niobium, niobium and rare earth elements are all important alloying elements in heat-resistant steels. The addition of alloying elements can improve the oxidation resistance, wear resistance and creep resistance of steel and reduce the cost of cutting. Heat-resistant steel with these elements has wide applications in many fields.
